You normally drive the south expressway between Calubang and Magallanes at an average velocity of
105km/hr (65mi/hr), and the trip takes 2 hours and 20 minutes. On a Monday morning, however,
heavy traffic slows you down and you drive the same distance at an average velocity of only 70km/hr (43mi/hr).
How much longer does the trip takes?
D = r * t
D = 65 * 7/3 = 151 2/3
151 2/3 = 65t
151 2/3 = 43t
Compare the two.
To find out how much longer the trip takes, we need to calculate the difference in time between the two average velocities.
1. Convert the time taken at the normal average velocity to minutes:
2 hours and 20 minutes = (2 * 60) + 20 = 140 minutes.
2. Calculate the distance traveled using the formula distance = speed × time:
Distance = 105 km/hr × (140 min / 60 min) = 245 km.
3. Find the time taken at the reduced average velocity using the formula time = distance / speed:
Time = 245 km / 70 km/hr = 3.5 hours = (3 * 60) + 30 = 210 minutes.
4. Calculate the difference in time taken:
Difference = 210 min - 140 min = 70 minutes.
Therefore, the trip takes an additional 70 minutes due to heavy traffic.